You all helped immensely to narrow the issues down, indeed!
@djn14 , @Sparqee : As for your click-on-rec-disarm bug: there’s no fix yet, but a workaround. Briefly, the clicking appears, when the Asio Guard buffer has the same size as the audio interface buffer. To avoid that, you can e.g. chose AG low with anything <256; AG Normal with anything <512, and AsioGuard High with values <1024. Please let me know if this helped with your specific issue.
The stuttering/ heavy dropouts when playing record-armed VSTi tracks is a different thing. This happens on some intel CPUs and we need to readjust our audio engine to get rid of this bug. This issue is prevalent on systems with a medium number of CPUs (12 … 32), as far as I can see from your info, and is present for low latencies, like 32. 64 and 128 samples. You could try raising the buffer to 256 or 512, for now. We are working on a solution for this.